Move WriteNotifier type into input module

It's a generic impl of `input::Notify` for `Write` types; as such, it
seems completely reasonable to include in the input module. Moving it
also serves to declutter main.

src/input.rs

@@ -23,6 +23,8 @@
 //! APIs
 //!
 //! TODO handling xmodmap would be good
+use std::io::Write;
+
 use glutin::{ElementState, VirtualKeyCode};
 
 use term::mode::{self, TermMode};
@@ -108,6 +110,15 @@ pub trait Notify {
     fn notify(&mut self, &str);
 }
 
+/// A notifier type that simply writes bytes to the provided `Write` type
+pub struct WriteNotifier<'a, W: Write + 'a>(pub &'a mut W);
+
+impl<'a, W: Write> Notify for WriteNotifier<'a, W> {
+    fn notify(&mut self, message: &str) {
+        self.0.write(message.as_bytes()).unwrap();
+    }
+}
+
 /// Describes a key combination that should emit a control sequence
 ///
 /// The actual triggering key is omitted here since bindings are grouped by the trigger key.

src/main.rs

@@ -69,14 +69,6 @@ enum ShouldExit {
     Yes,
     No
 }
-
-struct WriteNotifier<'a, W: Write + 'a>(&'a mut W);
-impl<'a, W: Write> input::Notify for WriteNotifier<'a, W> {
-    fn notify(&mut self, message: &str) {
-        self.0.write(message.as_bytes()).unwrap();
-    }
-}
-
 /// Channel used by resize handling on mac
 static mut resize_sender: Option<mpsc::Sender<glutin::Event>> = None;
 
@@ -108,7 +100,7 @@ fn handle_event<W>(event: glutin::Event,
             render_tx.send((w, h)).expect("render thread active");
         },
         glutin::Event::KeyboardInput(state, _code, key) => {
-            input_processor.process(state, key, &mut WriteNotifier(writer), *terminal.mode())
+            input_processor.process(state, key, &mut input::WriteNotifier(writer), *terminal.mode())
         },
         _ => ()
     }